The present invention relates to a circuit arrangement for processing, transmitting, and acoustically reproducing digitized audio-frequency signals which are processed in a signal processor together with digital control signals such as volume, tone, stereo balance, etc., and pass through an infrared transmission link whose receiver and a following power amplifier are incorporated in a loudspeaker box. The block diagram of such a circuit arrangement was made accessible to the public by the applicant at the September 1981 Berlin International Radio and Television Exhibition in the form of a chart. The infrared transmission link consisted of an infrared transmitter, an infrared receiver, and an optical-fiber cable interconnecting the transmitter and the receiver. As the infrared receiver and the following power amplifier are disposed within the loudspeaker box, this arrangement was called an "active" loudspeaker box ("active box").
The fiber-optic infrared transmission link has a certain disadvantage in that it limits the freedom to arrange the components of an audio system.